Recent heavy duty tires mounted on trucks, buses, and the like maintain the shape of the tread portion due to the tires having a low aspect ratio while having a circumferential reinforcing layer disposed in the belt layer. The circumferential reinforcing layer is a belt ply having a belt angle that is substantially 0° with respect to the tire circumferential direction, and is disposed so as to be laminated with a pair of cross belts. The technologies disclosed in Japanese Patent Nos. 4642760, 4663638 and 4663639, as well as in Japanese Unexamined Patent Application Publication No. 2012-522686, are conventional pneumatic tires that are configured in this manner.
Also, in recent years, retread tires have been gaining interest from the viewpoint of price and environment. Retread tires are tires where the remaining grooves have reached the end of their service live and the tread rubber is replaced so that the tire can be reused. They are produced by two methods, the pre-cure method and the remold method. Retread tires by the pre-cure method are produced by removing the tread rubber of the used tire by a buffing process to form a base tire, and a vulcanized pre-cured tread having the tread pattern of the original product is bonded to the base tire. Retread tires by the remold method are produced by removing the tread rubber of the used tire by a buffing process to form a base tire, then winding unvulcanized tread rubber around the base tire, and carrying out vulcanization molding using a molding die having the tread pattern.
For these retread tires, there is a demand to improve the yield of base tires.